Field of the Invention
The present invention relates to an articulated coupling device for a piston sealing device. The invention is an improvement of the sealing device for piston object of the patent WO 2015/011358 A1 published Jan. 29, 2015 belonging to the applicant, said device being particularly suitable for any piston operating under high pressure.
Description of the Related Art
The piston sealing device according to the patent WO 2015/011358 A1 is provided for a piston operating in a cylinder one end of which is closed by a fluid chamber, said piston comprising at least one piston head which comprises at least one fixed skirt, said head having, on the one hand, a piston bearing face for exerting a force on any mechanical, hydraulic or pneumatic transmission means and, on the other hand, a compression face opening into the fluid chamber and able to receive the pressure of a fluid.
Still according to patent WO 2015/011358 A1, the piston sealing device comprises a sliding skirt of cylindrical shape housed in a cylinder with a small clearance. Said skirt is also placed in the extension of the piston head on the side of the compression face and in the axis of said head.
It is noted that said sliding skirt is connected to said head by a mechanical inter-skirt connection which allows it to move in longitudinal translation with respect to said head while a pressure transmission channel arranged inside the sliding skirt crosses the latter from one end to the other in the axial direction.
The invention relating to the patent WO 2015/011358 A1 is also characterized by an extensible continuous segment of continuous annular shape which is interposed between the fixed skirt and the sliding skirt. Said segment comprises a segment inner cylindrical face subjected to the pressure of the fluid via the pressure transmission channel, a segment outer cylindrical face that can come into contact with the cylinder, a fixed skirt-side segment axial face held, directly or indirectly, in sealing contact with the fixed skirt, and a sliding skirt-side segment axial face held, directly or indirectly, in sealing contact with the sliding skirt.
Finally, the invention relating to the patent WO 2015/011358 A1 is also characterized by a sliding skirt spring which tends to bring the sliding skirt closer to the fixed skirt and to compress axially the continuous extensible segment or which, at least, acts as an abutment by keeping said sliding skirt from moving away from the fixed skirt.
On reading the patent WO 2015/011358 A1, it is understood that, in order to operate, the piston sealing device requires that the piston head, its fixed skirt and the sliding skirt always remain aligned. This configuration is ideal for hydraulic pumps and motors whose piston is oriented axially by the cylinder with which it cooperates.
In contrast, the piston sealing device according to the patent WO 2015/011358 A1 is not suitable for hydraulic pumps and motors whose pistons do not remain permanently parallel to the cylinder with which they cooperate. This is the case, for example, of bent-axis hydraulic motors with spherical pistons which nevertheless would see their volumetric and energy efficiency significantly improved by the piston sealing device according to the patent WO 2015/011358 A1.